Compact burner for an entrained-flow gasifier having no liquid cooling

ABSTRACT

A compact burner for the pressurized gasification of pulverized fuel dust for producing synthesis gas, wherein a plurality of concentric media channels transition into a conical burner tip. The burner tip provides a reduced contact surface on the reaction chamber side. The nozzle components of the burner tip are produced by selective laser melting, which permits a design for cooling by supplied media, such as fuel gas, flushing gas, or oxidation. A sliding guide having an intermediate seal is arranged between the nozzle components of two media channels to equalize temperature-driven linear extensions. The compact burner makes the expense for liquid cooling unnecessary.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2015/069412 filed Aug. 25, 2015, and claims the benefit thereof. The International Application claims the benefit of German Application No. DE 102014218219.0 filed Sep. 11, 2014. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a compact burner for the pressurized gasification of pulverized fuel dust for producing synthesis gas.

BACKGROUND OF INVENTION

In reactors for the entrained-flow gasification of pulverized fuel dust under elevated pressure to produce synthesis gas, pilot burners and main burners that are water-cooled several times on the reaction chamber side are used for supplying all the media. The water cooling processes are provided by pressure chambers, which present toward the reaction chamber an enlarged contact surface for the burner flame and the hot gases from the reactor. Mainly due to start-up and shutdown operations, the burner tip on the reaction chamber side has a limited service life. At the same time, particularly the burner cooling parts that are operated with cooling water and formed as closed pressure chambers require a high maintenance effort with regard to the recurring burner repairs. The various media to be supplied, such as for example fuel gas, pulverized fuel dust and oxidizing agent, have different temperatures and require structurally complex measures (e.g. corrugated expansion joints) for accommodating the different expansions of the burner channel walls.

A combined pulverized-coal burner with integrated pilot burner is known from DE 102007040890.

A gasification nozzle is known from CN2688677Y, wherein a sliding seal for compensating length changes is arranged at the joint between an inner spray tube and an outer spray tube.

SUMMARY OF INVENTION

The invention addresses the problem of providing a burner for the pressurized gasification of pulverized fuel dust for producing synthesis gas of which the burner tip achieves lifetimes comparable to conventional liquid-cooled burner tips without a cooling liquid being supplied.

The problem is solved by a burner having the features of the independent claim.

The cooling of the burner nozzles by means of complex, water-cooled, closed pressure parts is replaced by operating-media-cooled nozzles which are structurally designed accordingly.

The plant-related expenditure required for the existing water-cooling processes of the burner tip can be saved.

The burner nozzle parts are constructed in layers by means of generative processes and thereby largely produced in a finished state.

The process implemented for the layered construction uses a metallic powder, which is partially melted by means of a laser beam, at the end of which process the excess powder is removed and finally the desired component contour can be removed.

The generative manufacturing process is the SLM process (Selective Laser Melting).

Compared with the existing machining manufacturing process from forged parts, the production expenditure for the burner nozzles is lowered by more than 80%.

By using the laser melting process as the production process for the nozzle parts, it is possible to make contours of a satisfactory quality that cannot be created, or only with great difficulty, by conventional methods, such as for example narrow media channels or the temperature sensor channel, which is approx. 0.7 mm in size and follows the kinked nozzle contour.

By introducing temperature sensors at the burner nozzle parts in a position that is relatively protected in normal operation, conclusions can be drawn regarding the process conditions at the burner tip and the state of wear.

In addition to being cooled well by the operating media, the design of thin-walled nozzle parts results in optimization of the mixing of the reacting media and thus of the conversion of fuel and oxidizing agent.

For the purpose of adjusting to changing fuels, the adaptation of the swirl of the oxidizing agent is advantageous, this being achieved here by the introduction of a dividing wall into the oxidizing-agent channel. Here the medium can be fed to the burner tip in an axially non-swirled state in one channel and in a swirled state by means of guide plates or vanes in another channel. The quantity control of the two partial flows allows the desired resulting swirl to be set at the burner nozzle.

The use of sliding guides with sealing at the nozzles between the media alleviates the components of stresses caused by obstructed thermal expansion and eliminates the expenditure for additional measures such as expansion compensators in the media-channel walls.

Changing the nozzle during maintenance is simplified to a large extent by conventional welding without pressure tests.

There is no need for compliance with the technical regulations for pressure vessel construction, which consequently gives rise to a cost reduction for new construction and repair of the burner.

Advantageous developments of the invention are given in the subclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below as an exemplary embodiment, to the extent necessary for comprehension, on the basis of figures, in which:

FIG. 1 shows the basic construction of a media-cooled burner tip according to the invention,

FIG. 2 shows the arrangement of a sensor close to the burner tip,

FIG. 3 shows a main burner with a dividing wall in the oxidizing-agent channel,

FIG. 4 shows a conically-tapering burner tip with cylindrically-formed end pieces of the nozzle parts and

FIG. 5 shows a water-cooled, outer burner assembly which surrounds the burner tip.

DETAILED DESCRIPTION OF INVENTION

Identical elements are denoted by identical designations in the figures.

In FIG. 1 the basic construction of a media-cooled burner tip is shown, the contact surface (1) of which on the reaction chamber side is reduced. The nozzle parts (2, 3, 4, 5) are formed in such a manner that they are sufficiently cooled by means of a defined flushing gas quantity, such as for example nitrogen, or by an operating medium, such as for example fuel gas or an oxidizing agent. They are no longer parts of a pressure vessel and are adapted in their form to cost-effective production by means of generative processes, such as the SLM process (Selective Laser Melting). The existing material-intensive and time-consuming machining manufacturing from forged parts is reduced to a large extent. The media-induced different thermal expansion of the tubes (6) separating the individual burner channels is possible without hindrance at the sliding guides (7) of the burner nozzles in a stress-free manner and no longer requires any expansion compensators for compensation. Premature mixing of the media at the sliding guides (7) in the burner is prevented via seals (8). The compact nozzles (2) and (4) structurally ensure that the outlet contours on the reaction chamber side, which are especially important for supplying the oxidizing agent, are independent of changes arising from thermal expansions of the tubes (6) of the media channels.

Using the SLM manufacturing process for the nozzles makes it possible to produce with sufficient accuracy and sufficient surface quality very narrow, in particular also kinked, channels, such as at the pilot burner nozzle (2), of a kind that cannot be produced conventionally, or only with very great effort. The arrangement of an integrated swirl plate (9) results, on the one hand, in an improvement of the function of the burner and, on the other, in a lengthening of the lifetime of the nozzle through good cooling by using the media.

Furthermore, in the nozzle there may be arranged close to the burner tip, a sensor (10) for temperature monitoring, which allows conclusions to be drawn, both regarding the thermal load and the state of wear of the burner and also regarding the current operating state of the gasification reactor (FIG. 2).

As a further exemplary embodiment, the introduction of a dividing wall (12) into the oxidizing-agent channel of the main burner is shown in FIG. 3. The medium is supplied in a quantity-controlled manner to both channels, respectively via a supply connection piece in the rear burner region. The outer one of the two channels is provided in the nozzle region with an adapted swirl device (11), which imparts a rotational movement to this flow. The resulting angle of the entire exiting medium flow relative to the burner axis can thus be set via the control of the two partial volume flows. A guide plate, which is fastened on the dividing wall and formed in a spiral-shaped manner, or guide vanes set at an angle may be used for example in this case as the swirl device.

FIG. 4 shows, in an analogous manner, finished nozzle parts with cylindrically-formed end pieces (16) as variant embodiments for influencing the flame formation and the overall function of the burner.

FIG. 5 shows an exemplary embodiment of a complete compact burner with function-determining medium-nozzle parts, which are manufactured by means of the SLM process and cooled by the operating media, and of an enclosing water-cooled outer burner assembly 13 for use in the pressurized gasification of coals 15 entrained in dust form and other fuels for producing synthesis gas.

LIST OF DESIGNATIONS

-   1 Burner surface on reaction chamber side -   2 Pilot burner nozzle -   3, 4, 5 Main burner nozzle parts, cone-shaped -   6 Tubes for forming the annular media channels -   7 Sliding guides of the nozzles -   8 Seal -   9 Swirl plate for imparting a rotational movement to the entire     media flow -   10 Sensor for temperature measurement -   11 Swirl plate for partial media flow -   12 Dividing wall -   13 Outer, water-cooled burner assembly -   14 Oxidizing agent -   15 Supply point for pulverized fuel dust -   16 Nozzle parts with cylindrical media outlet 

1. A compact burner for the pressurized gasification of pulverized fuel dust for producing synthesis gas, comprising: a plurality of tubes which delimit concentric channels for supplying media, a burner tip which tapers conically, wherein nozzle parts of the burner tip are manufactured by selective laser melting, and a seal which is arranged at a sliding guide between two of the concentric channels.
 2. The compact burner as claimed in claim 1, further comprising: a swirl plate which is arranged in the concentric channel for the media.
 3. The compact burner as claimed in claim 1, further comprising: a nozzle part which merges at its conically tapering end into a cylindrically formed end piece.
 4. The compact burner as claimed in claim 1, wherein the media comprises a fuel gas, a flushing gas, and/or an oxidizing agent.
 5. The compact burner as claimed in claim 2, wherein the media comprises a fuel gas, a flushing gas, and/or an oxidizing agent. 